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Lossless (ALAC) iTunes downloads?

I recently started re-importing my CDs as lossless ALAC files, which are both much bigger and sound much clearer than the default 256 kbps compressed files. Is there a way to change the iTunes store setting so if I purchase music it downloads lossless? Or am I stuck with 256k or going old-school and buying a whole CD when I only want one song? Thanks!

PowerBook G4, Mac OS X (10.5.8)

Posted on Nov 18, 2010 6:15 PM

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89 replies

Mar 23, 2013 12:43 AM in response to ed2345

CDs are not "watered down". The human ear can only hear sounds up to about 20kHz - higher frequency is ultra-sonic. In discrete signal processing systems, which is what digital audio is, the sample rate only needs to be twice the highest analog frequency you are trying to reproduce. So sample rates higher than the 44.1kHz rate the audio CD uses would only be useful for reproducing audio frequencies that we simply can not hear anyway.


The sample bit depth of 16 bits per sample is more than enough to represent the dynamic range we can safely listen to. In fact most music can be represented with 12 bits.


When there are genuine quality differences between high definition audio and CD standard, it is the result of better mastering, not the higher sample rate or bit depth. In fact, chances are your computer sound server resamples the music you listen to before sending it to your speakers anyway - because to mix audio (so that multiple applications can use the sound system, such as hearing an e-mail alert while music is playing) the sources have to be the same sampling frequency and bit depth, so your computer audio system will resample just about everything anyway so they all match.


In every scientifically perfoermed ABX test where a high definition source was tested against the same source downsampled to CD standard, the listeners have not been able to tell the difference between high def sample rate and CD sample rate. And it makes sense that they can't, because the CD sample rate and bit depth is adequate to faithfully reproduce the analog waves that we are capable of hearing.


High definition audio is snake oil. It's fraud. Yes, technically there are more samples and higher bit depth to those samples, but that extra is useless. It does not benefit the reproduction of an analog wav in the frequency and range that we can hear any better than CD standard does.

Mar 23, 2013 4:02 PM in response to Chris CA

Let me try to explain it as simply as possible.

The audio you hear is analog. Sound waves are analog.


It's not like images that are not converted to analog before consumption, where higher definition allows for bigger and bigger images with better resolution (dots per inch).

The sound waves you hear are converted from digital samples to analog waves before you consume them.


The extra information in high definition audio does not allow the DAC to produce a better analog wave than the information in CD standard. 44.1 kHz sample rate is sufficient to accurately reproduce any frequency the human ear can hear. 16 bits per sample is sufficient to accurately reproduce any dynamic range the human ear can hear.


There is no benefit to the human ear with using a higher sample rate. Higher sample rates are beneficial to mastering due to the way many filters work but they are not beneficial to producing an analog wave for human audio consumption.


Your ear will not be able to distinguish the wave produced from converting a 24/96 master to analog and a sound wave produced from downsampling to 16/44.1 CD before conversion to analog.


You might think you can but that is all in your head. In an ABX test that is properly done (same master, both within 0.2 decibals of each other) you won't be able to tell if X is A or B more reliably than guessing.

Mar 24, 2013 3:00 AM in response to Chris CA

Let me try again. The sound you hear is caused by slight differences in air pressure, these pressure waves are analog, they have to be. Digital information for sound is converted to analog before your speaker can cause these slight differences in air pressure. This conversion is done by what is called a DAC - Digital to Analog conversion.


In essence, the an analog curve is fit to the digital samples. Additional samples will not allow for a better curve fit with frequencies below 20kHz - which is what humans can hear. Additional samples only will allow for frequencies to be represented above 20kHz but that is supersonic to the human ear, we can't hear those frequencies anyway.


Thus, the additional data in high definition audio does not make for better sound, not to the human ear. All it makes for is a bigger file size.

Mar 24, 2013 9:50 AM in response to Chris CA

If you have a straight line, you can take two samples and perfectlty represent that straight line from those two samples.


But lets say you have 27 samples along that straight line. Will be able to make a better straight line because you have more samples?


No.


If you have a circle, you can take three samples and from those three points perfectly reproduce that circle in the future. But lets say you took 59 samples around that circle. Will that extra data somehow allow you to draw a better circle in the future?


No.


It's the same concept.

With audio frequencies below 20kHz you can adequately represent them with CD sample rate.

Additional samples won't allow you to reproduce those frequencies any better.


Look up digital signal processing and read and learn. DSP has been around a lot longer than the CD and the math is very solid.

Apr 10, 2013 2:13 PM in response to Chris CA

Actually I care...


I appreciated Alice's explanation of sample rates and bit depth. I didn't realize that CD's could also be considered "compressed", but not in our common parlance definition of the word (where we use it to talk about lossy compression like a CD --> MP3). So even though CDs are encoded as a .wav, which we typically consider to be lossless, the encoding medium technically chops out the upper frequencies that we can't hear.


I also appreciate what you are (rudely) trying to say Chris, which is that there are no truly lossless tracks available on itunes, whether one chooses the "lossless audio codec" type of definition, or is focussed on sample rates and bit depth beyond what is even available on CD (I presume this is your definition of lossless... an original recording using a lossless codec that started with something that was still at 24/96).


I'd be happy enough with even the former definition of lossless being available. I guess I'll have to check out HD tracks

Lossless (ALAC) iTunes downloads?

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